Semiconductor devices are often fabricated through multiple processes, including a rough polishing and/or a finish polishing for generating a smooth surface on a wafer. The finish polishing is usually performed using a slurry which often contains a mixture of minerals, sludge or other suitable materials dispersed in liquid. For example, the slurry contains colloidal silica which is a compound of amorphous anhydrous silicic acid in a colloidal state. In addition, the slurry may include a chemical solution containing abrasive grains used for chemical mechanical polishing (CMP) or wafer lapping.